Energy storage technologies can provide energy security, fight climate change, and improve the value of current or future energy systems. Thermal Energy Storage (TES) is a key enable technology, it allows to stock thermal energy that can be further used for heating and cooling applications and power generation. The methods and tools used to analyse all the literature about the evolution of TES systems research are described in this paper. Bibliometrics is the science that studies, in a statistical way, the written publications of a certain field of research, and it is considered one of the few interdisciplinary research fields that can be extended to almost all scientific areas. The bibliometric analysis of the database Web-of-science (core collection) shows highlighted information in order to figure out the scientific outputs. The importance of the bibliometrics is to analyse a knowledge development from a strategic point of view in order to detect its evolution regarding the research in such a field and to detect which are the opportunities within this area. This study presents the publication evolution in TES field over the last two decades, per year, per country, per authors, per journal, and per TES technology, taking into account sensible heat TES (SHTES), latent heat TES (LHTES), and thermochemical energy storage (TCS), and considering the connection between authorship communities and country interactions. The communities are obtained from the co/authorships, regardless of the country or affiliation; this permits to view the size of the communities, as well as to identify collaboration opportunities between communities with low or no interaction. Furthermore, studies are included regarding detailed analysis on each TES technology, as well as other factors (such as funding) that can influence the current and future research.